Good advice, I’ve unconsciously done many of the things you’ve mentioned and currently work at one of the big international development organizations. It’s interesting how in more developed countries young people are fighting for jobs in the development world, I feel most young Latin American people don’t see this kind of career as an option and go for more “stable jobs” in the private/public sector. When I tell people what I do I usually get “oh this is such a beautiful job, so nice of you to sacrifice yourself for this cause” but in the end I’m getting paid more than most of my friends who work for multinationals. I’m definetely not in it for the status of being a world saver, even though I do want to make the world better by working in this area.
Sometimes people tend to make it very glamurous, the truth is those are very demanding and stressfull jobs. There is never enough people/resources to solve all the issues in this communitities we work, there is a lot of pressure and office work and bureacracy and taking donor on a field visits all weekend.
I would never discourage anyone from following this path but you should def know what you are in for. Volunteer will give you not only a great perspective of the field but also connections, most of my friends from my volunteering days are now coleagues, I know someone pretty much in every I.D. in the country and people spend their careers rotating through different organizations. Also learn spanish for real! At least if you are planning to work in south america is a must, most people who work in the european offices at my job also speak fluent spanish.